Recently, to prevent health hazard attributed to foods containing allergic substances, requests for information service by indication thereof have increased. The indication of foods containing allergic substances has been made obligatory with enforcement of amendments to the Statutes on the Food Sanitation Law in April, 2001. In particular, with respect to five items (specified raw materials) of eggs, milk, and wheat which cause allergy most often, and buckwheat and peanuts which cause serious symptoms, it has been made obligatory to perform proper indication over the entire distribution stage. There are individual differences as to what food people recognize as an allergen as the allergic substance. Thus, if a specified substance contained in the food is properly indicated even when the specified substance is contained in a trace amount, a person who ingests the food can know the presence/absence of the allergen contained in the food. However, it has been difficult to detect the presence/absence of a trace amount of a specified substance in a food having been heated or otherwise processed, by conventionally known methods for food analysis.
When a specified substance is used by a producer in his or her company, it is a matter of course that the specified substance can be indicated on processed foods. However, when a specified substance is used as an intermediate material of a final product, it is hard in some cases to confirm the presence/absence of the specified substance contained in a trace amount, particularly in a purchased intermediate material. Unintended inclusion may also actually occur.
For food manufacturers, it is important to precisely comprehend food additives such as processing aids and carry-over remaining in trace amounts or actual states of mutual contamination between manufacturing lines, and take proper measures as well as provide consumers with correct information based on the laws. Therefore, it has been desired to provide a technology of precisely analyzing allergic substances.
In Japan, buckwheat is a common food, but there are patients who exhibit an allergic response to the buckwheat. Many responses are of anaphylaxis type, and in the most serious case, the responses result in death. In the indication of foods containing allergic substances under the Food Sanitation Law, the buckwheat has been defined as one of the specified raw materials, and it has been made obligatory to indicate the presence of the buckwheat when the buckwheat is included in the food. But, there has been no appropriate method for measuring the amount of buckwheat. Therefore, a reliable method for measuring a trace amount component has been desired.
Thus, it is an object of the invention to provide a method for measuring the presence/absence of a specified substance in a food based on the findings obtained from attempts to construct primers specific to buckwheat, to identify the detection limit thereof, and to apply the primers to processed foods for the purpose of developing a method for precisely analyzing the presence/absence of the buckwheat included in the food.